Often several connectors of the same type are used in the same equipment. When, for example, cable bundles for vehicles are manufactured, the junctions between the terminals of each module and the conductors of the corresponding cable are made and then each module is inserted into a module holder in order to constitute a connector, which is generally a plug. In order to prevent a plug from being placed in a socket of the vehicle's equipment which is not that intended to receive it, means, called coding or polarizing means, are generally provided on each connector. These means include at least one key on one of the connectors, for example the plug, and a groove in the other connector, for example the socket, for receiving the key. Only two connectors for which the key and the groove occupy corresponding positions may thus be mated.
In current connectors of this type, it is the module-carrying casing which is provided with a coding key or keys. Consequently, there remains a risk of putting a module into a casing which is not the correct one. In addition, this makes it necessary to provide the same number of examples of module-carrying casings as there are examples of codings provided.
The present invention is intended in particular to provide a connector which meets the practical requirements better than those previously known, especially in that it removes the above drawbacks.
For this purpose, the invention provides a connector of the above-defined type, characterized in that a window is made in at least one of the said walls of the casing and in that one of the flanks of the module carries a projecting coding key which is oriented parallel to the plug-in direction and is placed so as to project into the window when the module is in place.
In order to allow the module to be plugged in, the window will generally extend as far as the front end of the casing, passing through the bottom of the latter.
Even when the module holder is held in the casing once the connector has been engaged in a complementary connector, it is desirable to provide means for holding the module in place although the connector has not been plugged in. This result may be achieved, in particular, by limiting the window, at the rear, in the plug-in direction by part of the wall of the casing which constitutes a flexible beam or transverse member having, on its internal face, a locking lug which engages with a projection provided on the flank of the module.
In order to allow entry of the key, the side wall of the casing in which the window (24) is made may include a step of height corresponding to the projection of the key of the module, above the level of the beam. The module may then have, to the rear, in the direction of insertion, an excrescence of height corresponding to that of the step.